The present invention relates to a method for mechanically cutting a groove modulated with information in a master disc having a copper surface. The cutting of audio signal recordings into metal surfaces is already well-known in the art, typical techniques being disclosed in German Pat. No. 66,942 and French Pat. No. 76 21636.
It is also already known to cut video signal recordings into record carriers by electromechanically cutting a groove modulated with video information into metal matrices, or masters, an individual groove being cut to a quiescent depth of less than one micron, as disclosed in U.S. Pat. No. 4,044,379 to Halter. Such a method requires the formation of a special surface on the metal master. According to the known method, an electrochemically deposited copper layer is smoothed in a subsequent special process step in order to make the surface to be recorded relatively flat.